Despite the resurgence of analytical interest in Schumann’s instrumental music and the “romantic turn” of the last decade (Vande Moortele 2017), analyses of Schumann’s symphonic music continue to be scarce. Studies that do exist (Smith 2014, 2016) typically use sonata theory’s system of defaults rather than examine the pieces’ low-level syntax. To address this scarcity, I analyze several of Schumann’s symphonic expositions using Caplin’s (1998) form-functional theory and Horton’s (2015) concept of “proliferation.” Using proliferation, I discuss a type of formal fusion are unique to Schumann: these fusions contain syntactically complete main themes and transitions—that is, each possess a beginning, middle, and end—yet are paired in such a way that encourages hearing them as fused units on a higher level. The fusions formed from proliferation reveal the internal workings of the more complex structures present in Schumann’s music, particularly by highlighting the relationships between what Caplin terms intrinsic and contextual functions. To demonstrate the kinds of formal fusion in Schumann’s music, I begin by showing how each unit is intrinsically complete, while still retaining a sense of openness. I then address this openness by showing how the two themes might be understood in relation to each other. My paper contributes to a growing field of research on nineteenth-century form by providing expanded tools for the analysis of nineteenth-century form. It also reveals elements of Schumann’s compositional style that have yet to be accounted for, whether in existing literature on nineteenth-century music or on Schumann.